An A340 pilot friend of mine recently explained to me that the climb
gradient for his A340 (as well as most other commercial a/c) as well as
the rate of climb slowly diminishes as the aircraft climbs into less
dense air, until stabilizing at about 500 fpm around 24000'. I have
noticed that the gradient is about 3-4 percent during the first 10000
feet and then seems to reduce to about 1.5% up in the flight levels. Can
anyone shed some light on this? (This example of course assumes that ATC
is not assigning altitudes and is leaving it up to the pilot).
zirkball